The present invention is directed to pumps and to methods of retrofitting pumps and particularly centrifugal pumps useful in systems for heating and cooling contents of flexible containers.
Many foodstuffs today, such as tomato paste, orange juice, crushed pineapple and diced tomatoes, are cooked and filled hot into flexible bags. The containers with the heated product (foodstuffs) must then be cooled for subsequent handling and storage.
An example of a system of the prior art for cooling contents of flexible bags is shown in FIG. 1 generally at 70. Referring thereto, the bags 72 enter the open-plastic belt conveyor 74 at one end into a first cooling station as shown generally at 76. Station 76 is shown in isolation in FIG. 2. The bag 72 is in a bath 78 of cooling water up to about its mid point. Overhead sprayers 80 spray cooling water on the tops of the bags 72. The bag 72 is conveyed by the mechanical action of the conveyor 74 to a gate 82 at the forward end of the station.
The gate 82 is formed by three stacked, upwardly rolling rollers 84, 86, 88. The actions of the conveyor 74 and the rollers 84, 86, 88 cause the bag 72 to rotate or turn over, as shown by arrow 90, about an axis generally perpendicular to the travel direction of the conveyor 74 to thereby partially mix the bag contents and to expose the bottom surface of the bag to the cooling water from the sprayers 80. The gate 82 is then pivoted down as shown by arrow 92, and the bags 72 are conveyed together to the next station for a subsequent cooling process, and so forth through the twelve or so stations.
There are a number of problems with the prior art system 70. One is that the overall process of system 70 is slow. It takes about forty minutes to cool the contents of the bag 72 from two hundred degrees down to below one hundred and twenty degrees Fahrenheit. Another problem is that the bags 72, and particularly when they are underfilled, occasionally get caught in the rollers 84, 86, 88 and break, spilling their contents. A further disadvantage of the prior art system 70 is that it occupies a large amount of floor space since it is approximately seventy feet long.
Other systems for cooling or heating the contents of flexible containers are shown in the following U.S. Pat. No. 4,384,463 (Rica et al.), U.S Pat. No.5,009,150 (Andersen) and U.S Pat. No. 5,370,174 (Silverstrini et al.). The contents of each of these patents and all other patents mentioned in this disclosure are hereby incorporated by reference in their entireties.